Introduction

Over the past 30 years, as coastal areas have been severely affected by a wide variety of human activities, traditional resource management has failed to prevent overexploitation and habitat degradation (Lauck et al., 1998; Claudet et al., 2006; Crowder et al., 2008). Ecosystem-based management (EBM) is a relatively new approach, and it is considered a promising solution to maintain ecosystem structure and function (Ruckelshaus et al., 2008). It represents an evolution from traditional management of single threats along single portions of ecosystems to large-scale management strategies within complex natural and socio-economic systems (Tallis et al., 2010). The aim of EBM is to sustain the long-term capacity of marine ecosystems to deliver the goods and services that society enjoys (e.g., seafood, clean water, protection from coastal erosion) while at the same time addressing the inherent trade-offs required to meet multiple management goals (Halpern et al., 2010). The consideration of human uses of and interactions with natural resources in EBM approaches improves the likelihood of achieving desired ecosystem outcomes (Gallagher et al., 2004). In 2005, McLeod et al. made a large contribution to defining EBM, but such efforts can still be considered as only the early stages of implementation and evaluation. The scientific community does not always agree about the principles that should inspire the management, conservation, and monitoring of marine environments (Worm et al., 2006; Bulleri et al., 2007; Hilborn, 2007; Stewart-Oaten, 2008; Lindenmayer and Likens, 2009). Although the importance of an ecosystem approach is widely accepted, its implementation is challenging in part due to perceptions that it is too complicated and has prohibitive information requirements (Tallis et al., 2010) and in part because it is ill-defined (Lotze, 2004). Scientific advice on the status of biodiversity and fish stocks, the effects of fishing and the role of marine protected areas (MPAs) are only small components in a complex management and decision-making process, in which scientific information often carries little weight in relation to immediate social and economic considerations (Jennings, 2004). Given the current worldwide biodiversity decline, there is an urgent need for immediate reassessment of present conservation strategies to develop initiatives aimed at reversing present trajectories of ecological degradation in the ocean.

Introduction

As marine ecosystems are plagued by an ever-increasing suite of threats including climate change, pollution, habitat degradation, and fisheries impacts (Roessig et al., 2004; Lotze et al., 2006; Jackson, 2008), there are now no ocean areas that are exempt from anthropogenic impacts (Halpern et al., 2008). In order to preserve marine biodiversity, ecosystem function, and the goods and services provided by resistant and/or resilient systems, marine reserves have been increasingly recommended as part of an ecosystem-based approach to management (Browman and Stergiou, 2004; Levin et al., 2009). Marine reserves are defined as “areas of the ocean completely protected from all extractive and destructive activities” (Lubchenco et al., 2003) and can be experimental controls for evaluating the impact of these activities on marine ecosystems. Growing scientific information has shown consistent increases in species density, biomass, size, and diversity in response to full protection inside reserves of varying sizes and ages located in diverse regions (Claudet et al., 2008; Lester et al., 2009; Molloy et al., 2009). However, most of these data are from individual marine reserves and therefore have inherently limited transferability to networks of marine reserves, which when properly designed can outperform single marine reserves for a variety of ecological, economic, and social management goals (Roberts et al., 2003; Almany et al., 2009; Gaines et al., 2010).

The concept of marine reserve networks grew out of a desire to achieve both conservation and fishery management goals by minimizing the potential negative economic, social, and cultural impacts of a single large reserve while still producing similar or even greater ecological and economic returns (Murray et al., 1999; Gaines et al., 2010). In addition, reserves networks can provide insurance by protecting areas across a region and spreading the risk that these sites may be impacted by localized catastrophes such as hurricanes or oil spills (Allison et al., 2003). The World Conservation Union's Marine Programme defines a network as “a collection of individual marine protected areas (MPAs) or reserves operating co-operatively and synergistically, at various spatial scales and with a range of protection levels that are designed to meet objectives that a single reserve cannot achieve” (IUCN–WCPA, 2008). However, general terms such as “co-operatively” and “synergistically” can have myriad meanings. Without a clear definition of a network, it becomes difficult to identify attainable management goals and design a process for evaluating whether the network achieves those goals. Besides, different management goals may in turn result in the need for different types of networks. The use of MPAs with varying protection levels together with no-take zones in multiple-zoning schemes adds another layer of complexity to network design and evaluation; however, partially protected areas are generally used to manage coastal uses and avoid conflicts (rather than for strict ecological purposes) and are therefore a function of the local social, economic, and cultural context. As we are here interested in the ecological effects of networks, for the purposes of this chapter, we focus on marine reserves because these areas are no-take and therefore offer greater ecological benefits than other types of MPAs that allow some forms of extraction (Lester and Halpern, 2008).

Introduction

Human-induced disturbance, e.g., through unsustainable fishery activities, can affect the ecology of coastal areas (Jackson et al., 2001; Lotze et al., 2006) and reduce the associated goods and services required for human welfare (Worm et al., 2006). Major concerns are rising over observed declines in the abundance of particular species as well as reductions in functional diversity and changes in food web structure (Pauly et al., 1998; Micheli and Halpern, 2005; Villéger et al., 2010). As a result, the conservation and restoration of marine biodiversity and functions is a major concern (Balmford et al., 2005). Marine protected areas (MPAs) are recommended to promote the recovery of exploited populations and conserve or restore habitats, ecosystems, and biodiversity (Lubchenco et al., 2003). Marine protected areas have also been recommended as tools for ecosystem-based management (EBM) of marine resources (Pauly et al., 2002; Halpern et al., 2010) and for restoration of ecosystem function (Mumby et al., 2007; Mouillot et al., 2008). However, some studies have failed to detect significant differences in ecological response variables between no-take and reference areas, or have criticized the design of existing studies, fuelling the view that the importance of MPAs as a management tool may have been overstated (Hilborn et al., 2004; Murawski et al., 2005; Osenberg et al., 2006).

Some attempts have been made recently to generalize the ecological effects of MPAs (Mosquera et al., 2000; Côté et al., 2001; Halpern, 2003; Micheli et al., 2004; Guidetti and Sala, 2007; Claudet et al., 2008; García-Charton et al., 2008; Harmelin-Vivien et al., 2008; Lester and Halpern, 2008; Lester et al., 2009; Molloy et al., 2009; Claudet et al., 2010). However, ecological effects can vary both in direction and magnitude (Micheli et al., 2004; Claudet et al., 2008; Guidetti et al., 2008; Lester et al., 2009; Molloy et al., 2009; Claudet et al., 2010). This heterogeneity in response to protection may stem from differences in the design or age of MPAs, life histories of focal taxa, the socio-cultural context within which MPAs are established, or a combination of these effects.

Early in their history, humans were just a new species, Homo sapiens sapiens, evolving within a broader history, natural history. As they continually struggled for survival, the world around them seemed probably hostile and inhospitable. Death from predation, starvation, and disease was rife. At the same time, like all other species, humans used their environment to meet their needs for food and habitat, and, over time, for some cultural artefacts. With the evolution of their customs and the invention of agriculture, humans settled and created the first civilizations. Their relationship with nature changed. Humans then shaped their environment, the use of nature turned into exploitation. Rationalization was not far off.

Changes wrought by humans on terrestrial realms were clearly visible. The awareness that these changes were impacting the natural environments led to the creation of the first nature reserves. Freud (1916) found in these creations a perfect parallel with the creation of the mental realm of phantasy, “withdrawn from the reality principle.” For him, “a nation whose wealth rests on the exploitation of the produce of its soil will yet set aside certain areas for reservation in their original state and for protection from the changes brought about by civilization” (Freud, 1911). “The requirements of agriculture, communication and industry threaten to bring about changes in the original face of the earth which will quickly make it unrecognizable. A nature reserve preserves its original state which everywhere else has to our regret been sacrificed to necessity. Everything, including what is useless and even what is noxious, can grow and proliferate there as it pleases” (Freud, 1916). Now, a trend in conservation practice is no longer to use reserves only as conservation fortresses outside of human “necessity” but rather to use them as management tools to improve the sustainability of human uses, creating trade-offs between conservation and use.